Well, you probably are going to continue taking hits to your self-esteem if you continue to live with him while he has sleep overs with his female "friend".
Things to do:
1. Expose the affair to those who will be supportive of your M. You will no longer lie to people about his affair.
2. New living arrangements. You need to protect yourself from this behavior, and that means him not coming home to where you live. Without particulars it's tough to make recommendations, but the general advice is to ask him to leave, give him a week to find a place, etc.
3. Then we work on making you fabulous.
M-47,W-40,No kids D-filed 5/27/2010 Piecing - 10/21/2010 -=Soon to be banned=-